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Formaldehyde Resin (formaldehyde + resin)
Selected AbstractsEuropean Standard Series patch test results from a contact dermatitis clinic in Israel during the 7-year period from 1998 to 2004CONTACT DERMATITIS, Issue 2 2006Aneta Lazarov The results of a 7-year retrospective study (1998,2004) from patch testing with the European Standard Series (ESS) establishing the frequency of sensitization in a contact dermatitis clinic in Israel are presented. 23 allergens were patch tested on 2156 patients, 1462 females (67.8%) and 694 males (32.2%). Atopy and asthma were present in 21.9% of the patients. One or more allergic reactions were observed in 937 patients (43.5%). The highest yield of patch test positives from the 1076 positive reactions were obtained from nickel sulfate (13.9%), fragrance mix (7.1%), potassium dichromate (3.8%), Balsam of Peru (3.6%), CL + Me-isothiazolinone (3.4%) and cobalt chloride (3.4%). Allergens which produced the least amount of positive results were primin and clioquinol. Allergic contact dermatitis (ACD) was established in 32.8%, whereas occupationally related allergic (8.0) and irritant contact dermatitis (5.6%) affected a total of 13.6% of the cases studied. The most common clinical forms of dermatitis were chronic dermatitis (47.7%) followed by acute dermatitis (22.8%), and lichenification and hyperkeratosis (7.9%). The hands (30.7%), face and neck (23.9%) and extremities (11.3%) were the most frequently affected areas. Four allergens in our study differed from the top 10 allergens in Europe namely: Cl + Me-isothiazolinone, formaldehyde, 4-tert-butylphenol formaldehyde resin and sesquiterpene lactone mix reflecting an existing difference in environmental exposure. Our study is the first to provide data on the frequency of sensitization and important allergens in the aetiology of ACD in Israel. In spite of the existing differences with Europe, we conclude that ESS is an appropriate screening system for the diagnosis of ACD in Israel. [source] P16 Eyelid dermatitis with positive patch test to coconut diethanolamideCONTACT DERMATITIS, Issue 3 2004Yves Dejobert Objective:, The aim was to detect a possible allergen in a patient with eyelid dermatitis. Patient and methods: a non atopic 27-year-old female presented with eyelid dermatitis since 3 months. This dermatitis persisted despite the fact she had stopped the use of make up; she had acrylic artificial nails since 2 months and sometimes used hair dyes;patch tests were performed with Finn Chamber® tests with readings at D2 and D3, according ICDRG criteria, with European standard series, additional series (including toluenesulfonamide formaldehyde resin), cosmetic, acrylates, hairdressing series, in 3 patch test sessions, using Chemotechnique Diagnostics® allergens. Results:, The only positive patch test was coconut diethanolamide (0.5% pet.)++ at D2 and D3. After removal of the shampoo containing this allergen, the dermatitis cleared. Coconut diethanolamide (cocamide DEA), tensioactive synthesized with coconut oil is widely used in shampoos, soaps, shower gels, barrier creams, washing up liquids, metalworking fluids, hydraulic oils. Involvement of eyelids is not frequently described in the literature with this allergen. Conclusion:, Coconut diethanolamide should be added in cosmetic series, and it should be useful to test this allergen in patients with eyelid dermatitis. [source] Curing kinetics of boron-containing phenol,formaldehyde resin formed from paraformaldehydeINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 11 2002Yanfang Liu A boron-containing phenol,formaldehyde resin (BPFR) was synthesized from boric acid, phenol, and paraformaldehyde. The curing reaction of BPFR was studied by Fourier-transform infrared spectrometry and differential scanning calorimetry. According to the heat evolution behavior during the curing process, several influencing factors on isothermal curing reaction were evaluated. The results show that the isothermal kinetic reaction of BPFR follows autocatalytic kinetics mechanism, and kinetic parameters m, n, k1, and k2, were derived, respectively. In the latter reaction stage, the curing reaction becomes controlled mainly by diffusion. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 638,644, 2002 [source] Allergic contact dermatitis to mango fleshINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 3 2004Sari Weinstein MD A 22-year-old white female student presented to the Emergency Department with a 2-day history of patchy pruritic erythema of the face, neck, and arms with periorbital edema. The eruption began as an isolated patch of nasal erythema, with subsequent extension to involve the entire face. Within 2 days, fine pinpoint papules were noted on the face, anterior chest, neck, and upper extremities. Periorbital edema was present without intraoral abnormalities or laryngeal changes. An erythematous, mildly lichenified plaque was noted on the ventral left wrist. The past medical history was significant for two similar, milder episodes of allergic reactions of uncertain etiology occurring within the previous 2 months. The previous eruptions resolved after treatment with oral loratodine and topical fluocinonide cream 0.05%. The patient denied any history of contact urticaria or new household or personal hygiene contactants, although she did report frequent ingestion of peeled mangoes. Her brother had a history of eczematous dermatitis. In the Emergency Department, the patient was administered intravenous diphenhydramine and a single 50 mg dose of oral prednisone. She continued treatment with a 5-day course of prednisone, 50 mg daily, with loratodine, 20 mg daily, and diphenhydramine as needed; however, no symptomatic improvement was seen over 4 days. She was then advised to restart fluocinonide cream twice daily. Patch testing was performed to the North American Contact Dermatitis Group Standard Series utilizing methods of the International Contact Dermatitis research group with Finn chambers. Mango skin and mango flesh harvested 5 mm below the skin surface were also placed in duplicate and tested under Finn chambers. Positive (1+) reactions were noted to nickel and p -tertbutylphenol formaldehyde resin, and bullous reactions were found to mango skin and surface flesh in duplicate (Fig. 1). Complete avoidance of mango led to resolution of the initial eruption. The clinical relevance of nickel and p -tertbutylphenol formaldehyde resin was thought to be associated with the wrist lesion immediately below a glued portion of a wristwatch strap and metal clasp. Figure 1. Positive patch test reactions, in duplicate, to mango skin (left column) and mango flesh 5 mm below the skin (right column) [source] Compatibility and viscoelastic properties of brominated isobutylene- co - p -methylstyrene rubber/tackifier blendsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008K. Dinesh Kumar Abstract Brominated isobutylene- co-p -methylstyrene (BIMS) rubber has been blended with hydrocarbon resin tackifier and alkyl phenol formaldehyde resin tackifier, and the compatibility between the blend components has been systematically evaluated. Dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) studies show that BIMS rubber and hydrocarbon resin tackifier blends are compatible at all blend proportions studied. However, BIMS rubber and phenol formaldehyde resin blends exhibit very limited compatibility with each other and phase separation even at very low phenolic tackifier concentration. Morphological studies of the rubber,resin blends by scanning electron microscopy (SEM) corroborate well with the DMA and DSC results. From the DMA frequency sweep and temperature sweep studies, it is shown that the hydrocarbon resin tackifier acts as a diluent and causes a decrease in the storage modulus values (by reducing the entanglement and network density) in the rubbery plateau region. On the other hand, phenol formaldehyde resin behaves in the way similar to that of the reinforcing filler by increasing the storage modulus values (by increasing the entanglement and network density) in the rubbery plateau zone. The relaxation time estimated from the different zones of frequency sweep master curves provides information about the influence of the two tackifiers on the viscoelastic properties of the BIMS rubber in the respective zones. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Properties of phenol,formaldehyde resin modified with organic acid estersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Rados, aw Mirski Abstract Properties of liquid and cured phenol,formaldehyde (PF) resin modified with esters were analyzed in this study. Esters with different carbon chain lengths, both in the acid and alcohol groups, were applied in the experiments. It was found that the modification of phenolic resin with applied esters does not deteriorate its pot life at the temperature of 20°C. It results in an increase of its reactivity at higher temperatures, manifested in the shortening of gel time at 130°C and a decrease of activation energy. Results of FTIR tests of polycondensed modified PF resin showed that products of alkali hydrolysis of esters not only catalyze the curing reaction of resin, but also become embedded in its structure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Environmentally friendly mixed tannin/lignin wood resinsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Hong Lei Abstract We obtained lignin-based wood adhesives satisfying the requirements of relevant international standards for the manufacture of wood particleboard. These were based on two different low-molecular-mass lignins. These lignin-based wood adhesives did not use any formaldehyde in their formulation; formaldehyde was substituted with a nonvolatile nontoxic aldehyde, namely, glyoxal. The last formaldehyde present, contributed by a fortifying synthetic phenol,formaldehyde resin, was also eliminated by the substitution of the phenol,formaldehyde resin with a natural, vegetable polyflavonoid tannin extract to which no aldehyde was added. This substitution brought the total content of natural material up to 80 wt % of the total adhesive. The adhesives yielded good internal bond strength results of the panels, enough to pass relevant international standard specifications for interior-grade panels. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Separation of dyes using composite carbon membranesAICHE JOURNAL, Issue 7 2009Sonny Sachdeva Abstract A composite, clay supported carbon membrane has been synthesized by carbonization of a blend of polyethylene glycol and phenol formaldehyde resin and the membrane thus obtained is characterized by separation of dyes. This membrane is subjected to permeability test using pure water which is found to be considerably higher than that reported in literature. It is subsequently shown to reject Acid Orange 7 dye from water with the rejection dependent on pressure and concentration of the dye which is typical phenomenon observed for a charged membrane. The separation data has been analyzed using the Space charge model and the membrane charge is estimated by minimizing the root mean square error between the experimental results and those calculated from the model. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Effect of aniline formaldehyde resin on the conjugation length and structure of doped polyaniline: Spectral studiesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 14 2005Ko-Shan Ho Abstract A DBSA (n -dodecylbenzene sulfate)-complexed aniline formaldehyde [AF(DBSA)1.0] was successfully synthesized with excess aniline (compared with formaldehyde) in the presence of n -dodecylbenzene sulfonic acid (HDBSA), which was complexed with aniline monomer before polymerization. The resin was carefully characterized with 1H and 13C NMR, electron spectroscopy for chemical analysis, and Fourier transform infrared and was demonstrated to be a polymer in which anilines were all complexed with HDBSA and became anilinium salts. A drastic decrease of the maximum absorption wavelength (ultraviolet,visible spectra) of DBSA-doped polyaniline [PANI(DBSA)0.5] was found when AF(DBSA)1.0 was mixed, and this resulted from the reduced conjugation length. A similar effect on PANI(DBSA)0.5 was found when free HDBSAs were mixed with PANI(DBSA)0.5. Visual inspection with an optical microscope revealed that PANI(DBSA)0.5/AF(DBSA)1.0 gave uniform morphologies in various compositions, showing possible miscibility for this system. X-ray diffraction patterns of PANI(DBSA)0.5/AF(DBSA)1.0 showed that the layered structure of PANI(DBSA)0.5 was still present but became shorter in the polyblend because of the presence of AF(DBSA)1.0. Solid-state 13C NMR spectra revealed that the reduced conjugation length was derived from the interaction of alkyl groups between HDBSA, complexed DBSA, and dopant DBSAs. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3116,3125, 2005 [source] Preparation of cationic latices comprising hollow thermostable particlesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2004V. N. Pavlyuchenko Abstract A method is described for the preparation of cationic latices comprising submicron hollow particles for a possible application as a thermally stable polymeric pigment in coatings or pigmented compositions on the basis of thermosetting polymers cured at temperatures up to 170,190 °C. The method is based on the deposition of melamine,formaldehyde resin in the form of cationic colloid onto anionic hollow particles resulting in the recharging of anionic hollow particles and the formation of an outer melamine shell, which provides thermal stability of the hollow particles at curing and application of pigmented coatings and compositions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2225,2234, 2004 [source] Studies on mechanical properties of sisal fiber/phenol formaldehyde resin in-situ compositesPOLYMER COMPOSITES, Issue 2 2009Qiuhong Mu Phenol formaldehyde resin (PF) reinforced with short sisal fibers (SF) were obtained by two methods, direct-mixing and polymerization filling. Impact and bending properties of resulting composites were compared. Under the same compression molding conditions, polymerization filled composites showed better mechanical properties than those of direct-mixed composites. The influences of fiber modifications on the mechanical properties of SF/PF in-situ (polymerization filled) composites have been investigated. Treated-SF-reinforced composites have better mechanical properties than those of untreated-SF-reinforced composites. The effects of SF on water absorption tendencies of SF/PF composites have also been studied. In addition, sisal/glass (SF/GF) hybrid PF composites of alkali-treated SF were prepared. Scanning electron microscopic studies were carried out to study the fiber-matrix adhesion. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source] Preparation and characterization of microcapsulated red phosphorus and its flame-retardant mechanism in halogen-free flame retardant polyolefinsPOLYMER INTERNATIONAL, Issue 8 2003Qiang Wu Abstract Microcapsulated red phosphorus (MRP), with a melamine,formaldehyde resin coating layer, was prepared by two-step coating processes. The physical and chemical properties of MRP were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) and other measurements. The flame retardant action and mechanism of MRP in the halogen-free flame retardant (HFFR) polyolefins (PO) blends have been studied using cone calorimeter, limiting oxygen index (LOI), thermogravimetric analysis (TGA) and dynamic FTIR spectroscopy. The results show that the MRP, which is coated with melamine,formaldehyde resin, has a higher ignition point, a considerably lower amount of phosphine evolution and of water absorption compared with red phosphorus (RP) itself. The data observed by cone calorimeter, LOI and TGA measurements from the PO/HFFR blends demonstrated that the MRP can decrease the heat release rate and effective heat of combustion, and increase the thermostability and LOI values of PO materials. The dynamic FTIR results revealed the flame-retardant mechanism that RP can promote the formation of charred layers with the P,O and P,C complexes in the condensed phase during burning of polymer materials. Copyright © 2003 Society of Chemical Industry [source] Electroinduced oxidative copolymerization of N -vinyl carbazole with methyl ethyl ketone formaldehyde resinPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 7 2004s Ustamehmeto Abstract In this study, a novel procedure to obtain the non-crosslinked, photoconductive, white form of the linear copolymer of N -vinyl carbazole (NVCz) and methyl ethyl ketone formaldehyde resin (MEKF-R) is reported. A possible mechanism of copolymerization is suggested. The yield of the copolymer is increased almost 10 times by the addition of catalytic amounts of ceric ammonium nitrate as an oxidant during the electrochemical polymerization of NVCz in the presence of MEKF-R in a divided electrochemical cell. Since cerium(III) is readily oxidized to cerium(IV) at the anode, the concentration of cerium(IV) remained constant and the deposition of green poly(NVCz) can be prevented. Copyright © 2004 John Wiley & Sons, Ltd. [source] Evaluation of performance of polyurethanes based on hydroxy alkylated cardanol formaldehyde resins under aging conditions,ADVANCES IN POLYMER TECHNOLOGY, Issue 2 2004K. Sathiyalekshmi Abstract Rigid polyurethanes were synthesized using hydroxy alkylated cardanol formaldehyde and hydroxy alkylated dimerized-cardanol formaldehyde resins and dicyclo hexyl methane diisocyanate. The studies on the aging (hydrolytic stability, absorption of water/toluene, chemical resistance, dimensional stability, and thermal stability) of these polyurethanes reveal appreciable stability. The performance of these polyurethanes was compared with elastoplastic polyurethanes synthesized with the addition of commercially available poly(ethylene glycol). The rigid polyurethanes are distinctly stable than elastoplastic polyurethanes under various aging conditions. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 91,102, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20005 [source] Valorization of an industrial organosolv,sugarcane bagasse lignin: Characterization and use as a matrix in biobased composites reinforced with sisal fibersBIOTECHNOLOGY & BIOENGINEERING, Issue 4 2010Elaine C. Ramires Abstract In the present study, the main focus was the characterization and application of the by-product lignin isolated through an industrial organosolv acid hydrolysis process from sugarcane bagasse, aiming at the production of bioethanol. The sugarcane lignin was characterized and used to prepare phenolic-type resins. The analysis confirmed that the industrial sugarcane lignin is of HGS type, with a high proportion of the less substituted aromatic ring p -hydroxyphenyl units, which favors further reaction with formaldehyde. The lignin,formaldehyde resins were used to produce biobased composites reinforced with different proportions of randomly distributed sisal fibers. The presence of lignin moieties in both the fiber and matrix increases their mutual affinity, as confirmed by SEM images, which showed good adhesion at the biocomposite fiber/matrix interface. This in turn allowed good load transference from the matrix to the fiber, leading to biobased composites with good impact strength (near 500,J,m,1 for a 40,wt% sisal fiber-reinforced composite). The study demonstrates that sugarcane bagasse lignin obtained from a bioethanol plant can be used without excessive purification in the preparation of lignocellulosic fiber-reinforced biobased composites displaying high mechanical properties. Biotechnol. Bioeng. 2010;107:612,621. © 2010 Wiley Periodicals, Inc. [source] | ||||||||||||||||